Dual balanced air meter for split engine



Aug. 2, 1960 J. DOLZA 2,947,298

DUAL BALANCED AIR METER FOR SPLIT ENGINE Filed May 7, 1959 INVENTOR.

C245? 090/2? BY A TTOP/VEV DUAL BALANCED AIR METER FOR SPLIT ENGINE Filed May 7, 1959, Ser. No. 811,691

'5 Claims. (Cl. 123-127) The present invention relates to an engine control system in which it is possible to operate the engine on less than all of the cylinders under normal or light load conditions but in which full engine operation is possible when the engine load exceeds a given value. The present invention is an improvement over copending application Serial No. 608,828, Dolza, filed September 10, 1956, now Patent No. 2,875,742, granted March 3, 1959.

As explained in the aforenoted copending application, it has been found that considerable economies can be realized when it is possible to resort to split engine operation, for example, being able to operate an eight cylinder engine on four'cylinders under moderate load conditions. The economy is eifected by the fact that individual cylinder efiiciency is increased when the individual cylinder load is increased during split engine op eration in contrast to reduced cylinder loads as occurs with full engine operation during lig t or moderate load conditions.

It is an inherent characteristic of an internal combustion engine to be most etficient under high load conditions. This is attributable to the quantity of air fed to the cylinders. Maximum air is supplied to the cylinders when the throttle is open, indicative of high load, therefore, more air may be compressed in turn increasing the compression pressure. Since engine efliciency increases with compression pressure and compression pressure increases with cylinder load, the desirability of split or part cylinder engine operation as a means for maintaining high cylinder loads becomes apparent.

' Split engine. operation has long been recognized as a theoretically desirable goal. However, the general complication of mechanisms which have been developed to achieve this type of operation have thus far precluded its commercial feasibility. The present invention relates to a greatly simplified split engine control system which has been operated over a considerable period of time and. has proved to be most satisfactory in operation.

The invention is illustrated with an eight cylinder although it is apparent that it may be applied to engines having any number of cylinders in excess of one. Separate air intake passages, throttles and manifolds are provided for the active and inactive cylinders.

. It is apparent that alternate firing cylinders should be selected for active or inactive cylinders. In other words, a normal firing order for an eight cylinder engine might be 1-8-4-3-6-5-72. The active cylinder group might then be cylinders 1-4-6-7.

In general, the operation of the split engine control system is such that when the manifold vacuum is above a given value, e.g., 4 inches of. mercury or greater, in the manifold serving the four active cylinders, the engine is operated on these four cylinders only and controlled by an active throttle device which regulates flow through one of the two air intake passages. When part or four cylinder. operation is eitected, an inactive throttle in the other air induction passage is moved to a full open position to prevent pumping losses in the inactive c ylin- 2,947,298 Patented Aug. 2, 1960 2 ders. At the same time fuel flow to the inactive" nozzles is also cut ofi. t t p Contemporaneously with the opening of the inactive throttle and the cutting oif of fuel flow to the inactive nozzles, means is provided for shifting an accelerator pedal controlled throttle linkage to a position increasing the opening of the active throttle beyond the amount which would otherwise exist during eight cylinder engine operation. This latter adjustment of the active throttle during four cylinder operation as well as its corollary in which the active throttle is moved towards a more closed position when eight cylinder operation is in effect necessary in order to provide a smooth transition between four and eight cylinder engine operation. The latter is necessary in order to make the transition at substantially consant engine torque.

The present split engine system is basically the same as that shown in copending application Serial. No. 736,915, Mick, field May 21, 1958. This present invention is an improvement in the Mick system in providing means for equalizing air flow to all engine cylinders during full engine operation. In any mechanical system for controlling the flow of air through more than one passage simultaneously an exact balance of flow cannot be obtained because of tolerances in the manufacture of parts. The subject dual balanced air meter insures equal air flow by providing two balance passages between the active" and 1nactive" air induction system. One of the balance passages is between intake headers posteriorly of the throttle valves. The other balance passage is be tween the air meter cavities anteriorly ot the throttle valves.

Valves are provided in the balance passages and are adapted to be opened during full engine operation tobalance air flow and to be closed during split engine operation.

Other objects and advantages will be apparent from a perusal of the detailed description which follows.

The drawing is a diagrammatic representation of a fuel system embodying the subject invention.

Referring to the drawing, a manifold is indicated generally at 10 and is of the divided header type in which individual air induction passages 12 and 14 are adapted respectively to supply air to four of the engine cylinders through individual cylinder intake passages 16 and 18. Throttle valves 20 and 22 are disposed in each of the induction passages as are contoured dilfusers 24 and 26. The diifusers and induction passages respectively coact to define venturis 25 and 27. Fuel nozzles 28 and 29 are disposed in the individual cylinder intake passages and are adapted to supply fuel to cylinders =30 when the cylinder intake valves 32 are open.

. In the present control system, as in the aforenoted copending application, a group of cylinders and associated air intakes are always active" whereas the remaining cylinders are normally inactive with the latter being activated only after the engine load exceeds a given value. In the present illustration, intake 12, throttle 20 and the four associated cylinder intake pasages 16 are the active part of the system whereas intake 14, throttle 22 and intake passages 18 constitute the normally inactive part of the system.

Fuel is adapted to be supplied to the nozzles 28-29 through a fuel injection metering device indicated generally at 34 which is shown and described in detail in copending application Serial No. 608,853, Dolza, filed September 10, 1956, now Patent No. 2,843,098 granted July 15, 1958. The fuel metering system functions in the same manner as described in the aforenoted copending applicaion and does not, per se, constitute a part of the present invention.

Air is drawn in through both induction passages as sarn'e'meteiing'signal in piezometer ring' 36 as total engine air-flow would produce on the single venturi used in'thea'forenoted Dolha application Serial'No. 608,853; Furthe'nsihceventuii depression" in piezometcr ring 36 is" proportionalitothe nozzlepressu're drop across all of the nozzles; 28"and with e'quafairflo'w restriction ineach' induction passage, due to coordinated (equal opening) positioningo fthe throttles; the venturi signal may be taken oif frotn" the active induction passage duringall operating conditions;

Fuel control mechanism" 34 is adapted to supply fuel pressure to conduit 42 in proportion to mass air'fiow. A branchconduit 441s supplied from conduit 42. Con duits 42and 44 respectively'lead to distributors 46 and 58 which inturnsupply the active and inactive nozzles through individualconduits50 and 52.

Throttles" 20 and" 22 are interconnected through a linkagemechanism indicated generally at 54 for synchronizedoperation' by the operator through the actu a tion of an accelerator pedal 5 6'. Accelerator controlled linkage operation is; however, modified by'other'mechanisms to be subsequently described;

The accelerator pedal controlled linkage 54 includes an arm Stffixed tonhe-active throttle shaft 60. Arm 5'8 isfart-iculated through a" link 62 to" a double articulated lever 64% The upper'portiorr 66 of lever 64 is' articulatedintermediatedts ends to'a link 68 connected at its other end to accelerator pedal 56. The lower endo f lever portion 66 -"is articulated at '70 to member 72 of the lever 64. mounted on a hired support 74.

The pivotal connection 70 between lever portions 66" and 79 has a link 7fi articulat'ed thereto and the other end ofwliich link is connected to a'- rod 78 of a servo device indicated generally at 8 Servo device 80 includes a pair of casingmenibers8Qland 84'whichperiph- Rod 7 8 is centrally fixed to the diaphragm" and extends through anopening sb irrcasing fi iz A spring 89'is dis= posed iii-servo chamber 90 and tends to bias diaphragm" It is possible, however; to'eliminat'e 86 to the" right. spring 89 if desired? The upper end of lever 64- has' a spring 92conne'cted thereto, the'other'end of whichis grounded at 94'. Assuming for themom'ent'that all other control forces remain' unchanged; it is apparent that as the accelerator pedalso is depressed thethrottle linkage system is such that the active throttle 20 will he' opened. It should'b'e' noted at this point that the pivoted" connection 70- be tween members 66" and 72 of double articulated lever 6'4 may be pivoted betweentwo positions byservo m'ech anism 80 in conjunction witli spring 89. When, asis the case during: eight cylinderoperation, the vacuum forces" on either side" of diaphragm" 86 are" substantially balanced, spring 89, through rod 78' and link 76; will shift pivoted connection point 70-in a rightward direction as shown in the dr awin'g; This action causes a counterclockwise rotation of member 66 movingthrottle 20'? inia clo's ing direct-ion; Aswill be subsequently considered: in greate-r" detail when the vacuum in chamber 90 overcomes spr'in'g3 89 the 'pa'tts' will be shifted-td-the dotted line -positionsto open th'rottle 20.- As will subs'e quentlyi be rn ore apparent; this differential movement of the active throttle 20. is f for the purpose ofreadjusting' the throttle=position to facilitate a smooth" transition between four and eight cylinder" operation.

During this eight or full cylinderoperation, actuation The lower end of member 72 is pivotally If of accelerator pedal 56 will cause the double articulated lever 64 to pivot about suppo'rt74. As will subsequent ly be considered in greater detail, however, during four or part cylinder operation, lever portion 66 will pivot about point 70 thus providing differential control of throttle actuation. a,

Active throttle lever 58 is articulated through a link 96 to an arnnilfi -loosely mounted'onthe inactive throttle valve shaft 100 so that the actuation of the active throttle may or may not 'afiect a similar movement of the inactive" th-rottle "252 depending on the actuation of other devices whichwillbe subsequently considered. A lever 102 is fi'ied'stmthe inactive' throttle shaft 100 and includes a tab portion 104 adapted to engage with the loosely mounted leve'i" 98: Assumiirg the system control forces are such that the inactive throttle 22 is in a closed position, as shown, then the levers 98 and 102 are in operative engagement andopening. movement of the active throttle 201Will likewise open the inactive throttle.

The various devicesl utilized to varythe subject fuel systembetweensplit andfull operationlwill now be considered. In general',..it has been found-that as long as themanifold vacuumin the active. portion 106 of mani foldl0-is above-a predetermined value, e.g.,tfour inches of mercury, most economical engineoperation will heachievedby split. orl four cylinder operation of the engine withlthe' remaining cyil'nd'ers beingvinactivated.

As already noted, inorder toprevent' pumpiilg losses inthe inactive engine cylinder it is desired to fully. open inactive throttle 22 during split engine operation. This full opening movement of throttle "22 is achieved by a servo mechanism 110: which includes a pair of casingmembers 112 and 114 peripherally clamping, a dia phragm ll' therebetween. A control rod 118 iscen'trally fiited to diaphragm 116 and projects through an opening 120 in the casing 112'and is connected to link 122 articulated to lever 102. A spring 124 disposed in chamber 125' between diaphragm.116 and casing 114 normally urgesthe lever 1'02 andthrottle 22' ina counterclockwise or closing: direction and under which con dition, as noted, tab 104" of lever 1'02 is'iin engagement" with active throttle controlled lever 98.

The actuation of servo I10 isfunder the control ofa' shiftvalve" device indicated" generally at 126. Device 1'26includ'es a plurality ofcasing members 128, and 132. Casing, 132fincludes aported' cylindrical opening within which a spool type valve member134is' slida'bly; disposed. Va1vemjeinber134" includes a stem 136px tending'toward casings 1'28 and 130. and upon which a pair of flexible diaph'ra'gms. 138 and 1 40' are centrally mounted. The first diaphragm 138 is peripherally clamped" between"'casin'gs' 1-'28 and 13.0 Iwhilethe second and smallerdiaphragm 140 is. peripherally" clamped by the casings 130an'd'132: Chamber 14-2 defined by casing 128' and diaphragm.138"is"connected'through a'pfas sage 144 with the active manifold 106' whereby active manifold vacutnn is at all timestransmittedto the chamb'er.

Chamber 146"defined by 'diaphragms138' and 140 and easing -130"is"communicated through a conduit148"with" the inactive manifold 150 and" likewise" is at alltimes subject to the"'vacuumforce"extant therein; A? spring 152 is also disposedfin vacuumwhamber 142 andbiases' spindlevalve' 13'4in'a'rightward direction which; other" control forces permitting; causes conduit 154fcommunieating with chamber 125 of servo'110 to beexh'austed to theatmosph'ere through an exhaust port 158 in casing 132'. In such case spring 124 would move inactive throttle 22 in aith'rottle closing'direction.

So long as the vacuum in manifold 106 exceeds that in manifold 150 by 'a' difierential offour inches of mer-' cury, the vacuum force in chamber 142 will be sufiiciently. strong to overcome spring 152: as well' as the vacuum force in chamber 146 to shift' value 134 totheleftl Urider this circumstance active manifold vacuum from conduit 160 will be admitted from valve casing port 162 between the lands of valve 134 where it will act through conduit 154 on inactive throttle diaphragm 116 to shift the diaphragm to the right against the force of spring 124 to fully open the inactive throttle.

At the same time, the vacuum forces from manifolds 1 06 and 150 are respectively transmitted through conduits 164 and 166 to chambers 90 and 91 of accelerator control linkage servo 80. The same vacuum differential will cause diaphragm 86 of servo 80 to be shifted to the left moving the pivotal connection 70 to its leftmost position in which a stop 168 on member 72 of lever 64 abuts a fixed stop 170. The leftward movement of pivotal connection 70 causes member 66 of lever 64 to be rotated in a clockwise direction increasing the opening of the active throttle in order to maintain a constant engine torque for smooth transition to four cylinder operation, supra. As noted, supra, lever 66 now pivots about point 70 providing differential control whereby the active throttle 20 will open to a greater extent than during corresponding eight cylinder operation.

Contemporaneously with the shifting of the throttle linkage and 'the opening of the inactive throttle, a servo valve device 172 is adapted to cut off the flow of fuel to the inactive nozzle distributor 48. Servo valve device 172 includes a pair of casing members 174 and 176 pcripherally clamping a diaphragm 178 therebetween and thereby forming a pair of vacum chambers 180 and 182. Vacuum chambers 180 and 182 in turn communicate through conduits 184 and 186 with active and inactive manifold vacuum conduits 144 and 148. A control rod 188 is centrally fixed to diaphragm 178 and terminates in a valve portion 190 which, when the predetermined vacuum differential exists between manifolds 106 and 150, is shifted to the right against the force of spring 192 to cut ofi the flow of fuel from conduit 44 to nozzles 29.

The transition from split or four cylinder operation to eight or full engine operation is, as noted, effected when the vacuum in the manifold 106 drops below a pre determined value, e.g., four inches of mercury. When this happens the force of spring 152 acting on the shift valve device diaphragm 138 will cause valve 134 to be moved to the right atmospherically venting inactive throttle servo chamber 125 and causing the spring 124 to move the inactive throttle towards a closed position and operatively engaging inactive throttle levers 102 and 98 whereby synchronized operation of the throttles will thereafter take place.

Closing the inactive throttle substantially equalizes the vacuum in manifolds 106 and 150 under which conditions the vacum forces on either side of linkage controlling servo diaphragm 86 will be substantially equal and spring 89 will shift the active throttle 20 to a more closed position, supra. Again, the equal vacuum in manifolds 106 and 150 will be transmitted to fuel cut-off valve servo chambers 180 and 182 permitting spring 192 to open valve 190 and thereby initiating fuel flow to inactive nozzles 29.

During eight or full cylinder operation the active and inactive manifold vacuums are equal resulting in no vacuum force differential acting on shift valve diaphragm 138. However, when the vacuum in chamber 146 of the shift valve device 126 exceeds a given value, e.g., inches of mercury, it will act on the small diaphragm 140 with suflicient force to overcome spring 152 and shift the valve 134 to the left. This again fully opens the inactive throttle which once again causes the servos 80 and 172 to again adjust the throttle valves and fuel flow to four cylinder operation.

Up to this point it has been assumed that air flows through active and inactive induction passages 12 and 14 were equal during full or eight cylinder operation. As already noted, this assumption is not necessarily correct and that due to slight differences in manufacture, the air flow may vary from one passage to the other.

To insure balanced air flow between induction passages 12 and 14 it has been found necessary to provide means for interconnecting these passages during full engine operation. More specifically it has been found to be desirable to connect the air induction systems both anteriorly and posteriorly of throttle valves 20 and 22. Accordingly, longitudinal passages 200 and 202 are formed through tapered diflusers 24 and 26. Passages 200 and 202 are interconnected by a conduit 204. Thus induction passages 12 and 14 are adapted to be communicated anteriorly of throttles 20 and 22. This connection will compensate for any fiow inbalance due mainly to size variations between the active and inactive venturis.

Another balance passage 206 is formed in the header wall 208 between passages 12 and 14. Passage 206 is adapted to compensate for any flow inbalance created posteriorly of throttles 20 and 22.

Balance passages 204 and 206 respectively include valves 210 and 212 which are interconnected through levers 214 and 216 and a common actuating rod 218. A servo device 220 is adapted to control the actuation of rod 218 and hence valves 210 and 212. Servo device 220 includes casings 222 and 224 peripherally clamping a flexible diaphragm 226 therebetween. Rod 218 extends through an opening in casing 224 and is centrally fixed to diaphragm 226. Servo chambers 228 and 230 are re spectively connected to active manifold vacuum conduit 144 and atmosphere through conduits 232 and 234.

Since air flow through induction passages 12 and 14 is naturally and desirably unequal during split. engine operation, the higher vacuum in conduit 144 will be transmitted through shift valve device 126 and conduit 154 to servo chamber 228 where it will overcome a spring 236 to raise rod 218 and close valves 210 and 212. During full engine operation the active manifold vacuum in conduits 144, 154 and 232 is not of a sufficiently high value to overcome the force of spring 236 whereby the'latter will move diaphragm 226 and rod 218 downwardly to open valves 210 and 212. In this way air flow through induction passages 12 and 14 and to the cylinders supplied thereby will be equalized during full or eight cylinder operation.

It is apparent that the subject invention has been diagrammatically represented in order to simplify the understanding of its operation. It is also apparent that the substance of the subject invention may be embodied in various structural arrangements within the intended scope of the hereinafter appended claims.

I claim:

1. A charge forming device for an internal combustion engine comprising a first air induction system for supplying air to certain cylinders of the engine, a second air induction system for supplying air to the remaining engine cylinders, first and second throttle valves for respectively controlling the flow o air through said first and second systems, means for supplying fuel to each of said air induction systems in accordance with engine demand, means for synchronizing the actuation of said throttles, means responsive to the engine vacuum differential in said air induction systems posteriorly of said throttles for fully opening one of said throttles when said differential exceeds a predetermined value, additional means responsive to said predetermined vacuum differential for moving the other throttle to a more open position when said one throttle is fully opened, means operable in response to said predetermined vacuum differential to cut off the flow of fuel to the air induction system associated with the fully opened throttle, and means for equalizing air flow through said induction systems when all engine cylinders are operative to supply power.

2. A charge forming device for an internal combustion engine comprising a first air induction system for supplying air to certain cylinders of the engine, a second air induction system for supplying air to the remaining engine cylinders, first and second throttle valves for respectively: controlling-v the flow of air through said first and: second systems,'- means for supplying fuel to each of s aid air: induction: systems in accordance with enginedemand means for synchronizingthe actuation of said throttles, means: responsive to the engine vacuum differential irnsaid-- air inductionisystems posteriorly of said throttles for fully opening: one of said throttles when said: diife'rential exceeds a predetermined value, additionalmeans responsive to said predetermined vacuum differential fo'r movingithe other throttle to a more open position vvhen said one throttle is fully opened, means operable in response'torsaid predetermined vacuum dif ferential to cut ofi 'th'e flow of fuel to-the air induction systnt'. associated. with: the fully opened-- throttle; and valve meanssfor interconnecting said induction systems to equalize air flow therethrough when all" engine cylinders; arex operative to supply: power.

3 i Azchargeaformingzdevice for an internal: combustion engine 'cbmprisingea first airinduction system fo'r supply? iiig air to certain cylinders of the" engine,- a second air indl'iction system for supplying; air tothe remaining" engine: cylinders, first and second throttle valves for re spectivelyfcontrollingr the flowr' of air through said first and second system's-, means for supplying fuelto each ofi said ai'r induction syst'ems inr accordance With engine demand, means for'synchroniz'ing .the' actuation of said throttles;- means responsive: to the engine vacuurrr differential in said air induction" systems posteriorlyof-zs'aid throttles: for fully opening: one of said' throttles when said: differential exceeds a predetermined: value-,H additio'nali means: responsive to said predetermined vacuum diifrentialzfor movin'g' tlie other throttle to a more openposition when said one throttleis' fully opened, means operable in res'p'oi'ise to said predetermined vacuuiri differential to cut oif'th'e fiow'ofi fuelto the air inthietion system associated with the fully opened throttle, and first and secondvalves for respectively interconnecting said-induction systems anteriorly and posteriorly ofsaid' throttle valves to equalize air flowthrough said systems When all engine cylinders are operativeto supply go'wer. 4. A charge-forming device as set'forth in claim 2" iii-which saidvalve means comprises afirst passage interconnecting saidinduction systems anteriorly of the throttle valves, a second passage interconnecting said systems posteriorlyi of said throttle valves, valves respectively disposed in said passages, and a common actuatingdevice" forsaid latter valves, said device being adaptedtoclose saidvalves when fuel flow is cut off to one ofi the-air induction systems and to open-said valves when all: engine cylinders are operative'to supply power. 5; A charge forming; device asset forth in clainr4 in vvhich said common actuating device includes a servo; mechanism compfrisingapair of easing members, a lienible' diaphragm" peripherally clamped between said cas= ing; members, a rod member centrally fixed to said dia-' phragrn and operativelyconnected tothe first and secand passage valves; said casing members respectively coacting with-said diaphragm to define a pair of chambers, a spring member biasin'gsaid diaphragm in a direction tendingito open saidvalves; and conduit means respectively. connecting. said chambers with the first and second air: inductio'n systems posteriorly ofthe throttle valves; and a spring'member adapted to bias said dia phra gm. in a direction to open" said first and second pas sage-valves wheri the vacuum'forces in saidchambers are substantially equal, said diaphragm being adapted to clos'e the: latter valvesr when the vacuum in one of said induction systems exceeds" that of the other system;

No references cited; 

